class phone:
    __is_5g_enable = False

    # def __init__(self, __is_5g_enable):
    #     self.__is_5g_enable = __is_5g_enable

    def __check_5g(self):
        if self.__is_5g_enable:
            print("5g开启")
        else:
            print("5g关闭，使用4g网络")

    def call_by_5g(self):
        self.__check_5g()
        print("正在通话中")


phone = phone()
phone.call_by_5g()
